Safety-switch.



H. B. SHREVB.

SAFETY SWITCH.

APPLICATION FILED JAN.11, 1912 1,114,813, I Patented 0015.21", 1914.

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Be it known thatI, HARRY B. Smmvn, a citizen of the' United States, anda resident of Chicago, in the county of Cook and State of Illinois, haveinvented certain new' and useful Improvements in SafetyfSWitches; and Ido hereby declare that the following is a lfull, clear, and exactdescription thereof, reference being had to the accompanying drawings,and to the letters Iof reference marked thereon, which lform a part-ofthis specilication.

This invention relates to certain novel improvements in electric safetyswitches'more particularly intended for 'use in connection with elevatorsystems, movement of the elevatoi'when any of the doors or gatesopening. into the elevatorshaft are opened or stand in open position.

The general featuresof thistype of switch are familiar and include aswitchmechaiixed in the elevator-shaft and a member carried by the dooror gate, .the switch mechanism heilig so arranged that the electriccircuit controlled by the switch is broken whenever thev door or gate isopened and remains thus until the door or gate has been moved intoclosed and locked position, the member carried by the door engaging andoperating' a movable member of the switch to close the circuit. Theelectric circuit controlled by the switch embraces the motorl whichoperates the elevator and also-a brake-mechanism which is normallyinoperative as long as the electric circuit is closed.

The invention consists of the novel teatures of the switch ashereinafter described and more particularly pointed out inthe appendedclaims.

f In the drawings r-Figure 1 is a front elevation of Jthe improvedswitch mechanism with the front cover of the casing that in- 'y closesthe switch mechanism removed, and

with the parts of the 'switch shown in position as when the circuit isopen. Fig. i! is a similar view showing the parts in position as whenthe circuit is closed. Fig. is a View like Fig. 2-showin the parts ofthe switch in closed position ut with the members which operate it atainal limit of 'their l Fig. 4 is a, view representing a through theswitch in a l Fig. 5, Fig. 5. is va cross-section tbnnuglr- --the switchmovement. .vertical section to stop or'prevent- Specification of LettersPatent. i Application inea new@ 111918. sensi nu. 741,412.

plate` 18` which is of Ufform Y rammed' oct. 27, 19111.

plane .indicated by. the line- 5,'-5 of Fig. v

Referring now to-that embodiment of my invention illustrated in the'drawings, 10'v1n. dicates a casing orhousing that incloses theswitchmechanlsm and is adapted-.to be at-- tached tothe wall of theelevatorshaft'in 'a positionin alinement with a switch .operatf ing baror arm 11 carried by the movable,v

door or gate. Thesev are so arranged relaf tively to eachother, thatwhen. the dooris moved to closed position, the arm lllwill .operate theswitch toelose the circuit.- l.

12 indicates'a blockof insulatingmaterial which extendstransverselyofthe-casing 10- and is rigidly connected to the-bottom wall 10aof-saidl casing in any suitabl manne'r.

On the front edge of said block 12-(the leftf l hand edge as shown '1nthe drawings,)` are fixed ,two contact. members 13, 13 whichare `spacedapart and constitute terminals ,ofi the electric circuit of the elevatorsystemwSaid contact members .as shown are parts ofi dat bars 13, 13.*,which, having their endsbent 1' downwardlyand engaged against theiront.'

edge of said block, arey attached. by suitable screws to the top of theblock, and have their other end parts bent. downwardly andl om' gagedagainst the rear edgeof saidblock and then odset parallel tothe bottomwall of the box 4and spaced therefrom to provide supports for bindingposts 14, 14 by means-- of, which they areconnected with the conductorwires 15, 15 of the electric system. Said bars 13, 13, areso-dimensioned-and spaced part and the block 12 itself is lmade ofsuch'thickness that a.- snitable air space or gap for insulation purposes-isprovidedsbetween said bars and the bottomwall, side walls and cover.plate of the box.

16 indicates al vmovable insulationnbfoclr arranged to slide on thebottom wall or lie casing which. is preferably -provided with )arallelspaced bearing ribsl rising thereromr and. extending box. j

17, 17 indicate contact members fixed on the rear edge ofthe block 16inline with the fixed contact members '13 13 and ad for.contact-'therewith v block i6 is moved toward the fixed block -12longitudinally.v yof thel 'tor-that purpose. Said contact members 17,

as shown in thdrawi'ngs, form part 'foi a th the .legs

'ofv the fU-g bent dowmvardlyl against the rear.'

w en the movable apted edge o1' the block 16 and the transverse. memberof the Ul engaged against and at` tached by suitable screws to the topface of,

said block. In this case, as in the case of the fixed contact members,the metal U-platev Y roviding the contact members 17, 17 and the movableblock 16 itself areso proportioned and dimensioned with reference to thebottom and side walls of the casing and' the cover-plate thereof that anefficient air-A gap is provided for the purpose of insulating thecontact members 17 17 and the part .of the plate connecting them fromthe -metallic walls of the casing.

The movable insulation block 16 is mounted on 'a-reciproc'ableplunger-rod 1 9vvhich is located midway between the two Contact members17, 17. Said plunger-rod has reciprocatory bearing at its rear end in asleeve 20 secured in a suitable aperture or recess opening through thefront edge of the fixed insulation block 12. vThe Jforward end of theplunger-rod is, as shown, made integral with a buffer-block 21 thatprojects through and has' bearing in an opening formed in the front sidevva.ll.10c of the casinv. Said butter-block has laterally extend# y ingshoulders 22 at its rear end which are adapted for engagement againstthe inner surface ofthe said front side wall 10 and -act to limit theoutward movement of the plunger. The buffer-block 21 is in line with themovable arm 11 carried by the door or gate of the elevator-shaft and isadapted to l)be struck thereby when said door or gate is moved to closedposition. y

The plunger rod 19 extends through and has bearing in a sleeve 23 fixedin a suitable aperture in the movable insulation block 16. Said sleeveis made slightly larger in intei-nal diameter than the diameter of theplunger-rod so as to provide a loose'bearing for said rod. This permitsa loose lay of the movable switch member on .the p unger` rod adaptingit to swing into a position at a" osition at right slight angle to itsnormal for a purpose angles to said plunger-ro presently to beexplained.

The sleeve 23 has at its front end an inwardly extending flange 23 whichforms-a seat for coiled springs 24 and 25 mounted on theplunger-1od,-the first, namely, the spring 24 being placed on said rodat the .rear of said angenand the second, namely, 'the spring 25 bein'gplaced on 'said rod 1n front of said flange. The rear end of the 'spring24 enga. es against the fixed insulin tion block 12 w ile the forwardend of the spring 25 engages against the rear end of the buffer-block21. The latter spring is heavier .than and is not so easily compressibleas the spring 24, the purpose of which difference will nowaappear.

The operation of my improved switching mechanism is as follows: Thewpartg-normall standin the relative-'positions indicate in'Fig. 1 whenthe door or.- gate is .in

I open position; In this position the movablecorita'cts 17 are separatedfrom the ixed'contacts 13 and vthe -electric circuit open.

the door moves ytoward closed position the arm 11, just before the dooror gate reaches wit out compressing the'spring 25 and bef fore thebuier-block 21 an the plunger-rod 19 has reached the full .limit of itsinward movement. A further movement of said buffer-block and plunger-rodwill be'. permittedby. reason ofthe compressibility of the spring 25which comes into action after. the contactual relation of the fixedand-sinovable y'contact members 'has been' broughtzirv about. Thus somevariation '-in the finalpo.-

sition of the armll carried bythe 'door-vor.

gate ispermissible without danger of'lailure of the operation of the Onaccount' ofthe flexibility of the movable insulation blockv 16onthe'plungerfrod 19 and its capabilityof assuming a position at anangle to its right angular position on said rod, the proper closing ofthe switch is insured in case by reason of arcing or'otherwise betweenthe opposing contact members'- a lug or excrecence 1s formed'on one orthe other s o that one vpair of opposing contact `members are broughtinto engagement be- ,scfo're the other.

the two opposing contact members, one.o f

Under these circumstances which carries lthe said lug or excreccnce willengage' first before the plunger-rod has reached.- its linal position,and the othericontact` member of the movable switch member willbecarried forward notwithstanding thel stoppage referred to until it isbrought into engagement with its associated fixed "com tact member, theparts assuming suchtion as indicated in dotted lines in Fig.12'.f

I claim as my invention y parts -as described.

1. A switch device of the kinddescribed` comprising theV combination ofa casing, of a fixed insulation block secured within said casing,laterally spaced contacts carried by.

said block, a movable insulation block in.

said casing, laterally spaced contacts carriedA thereby each in linewith and adapted for contact with one of the rst named contapts, areciprocable plunger in said casin '1 on which said movable insulation sloosely mounted, a buer 'fixed on said plunger projecting without saidcasing and provided with stops to limit its outward movement, aspring'interposed between said movable insulation biock and said fixedinsulation block, and a more rigid. spring interposed between saidbuiier block and said movable insulation block.

2. AV switch device of the kind described comprising the combination ofa casing, of a fixed insulation block secured within said casing,laterally spaced contacts carried by said block, a movable `insulationblock in said casing, laterally spaced contacts carried thereby each inline with and adapted `for contact with one of the first named contacts,

a reciprocable plunger in said casinor on which said movable insulationblocc vis loosely mounted, said plunger bein provided with a buierat oneend whic vprojects without said casing, means for limit ing the outwardmovement of said plunger,

and yielding means acting to resist movementl'of the mova'ble insulationblock in either direction on said 3. A switch device o comprising thecombination of a casing, of a fixed insulation block secured within saidthe kind described casing, laterally aced contacts carried by saidblock, a Inova le insulation block in said casing, laterally spacedcontacts carried thereby each in line with and' adapted for contact withone of the rst named contacts, a reciprocable plunger in said casingl onwhich said movable insulation bloc is mounted, said plunger beingprovidedwith a buffer at onev end which pro Y 'ects without said casing,means for limiting the outward movement of said plunger, ielding meansinterposed between said two -'insulation blocks acting to resist themovement of one toward the other, and yielding means interposed betweensaid movable block and a fixed part of said plunger actto resistmovement of said block toward the buffer end of said plunger, beingcapable of eater resisting the first named yielding means.

In testimony that I claim the foregoing as my invention I aiYiX mysignaturev in the presence of two witnesses, this 30th day of December.,A.. D. 1912.

HARRY B.- SHREVE..

ing

force than .Witnessesz GEORGE R. WiLniNs, T. H. ALiiznDs.

the latter

